Manufacturing a printhead that has relatively high resolution and print-speed raises a number of issues.
One of these relates to the layout of nozzles on a printhead, and the provision of fire control signals to the nozzles. In a pagewidth printer, the simplest layout is one in which nozzles extend in a straight line across the pagewidth. A fire signal is provided to all nozzles simultaneously, resulting in a straight line of dots across the page.
The main difficulty with this approach is that it requires relatively high peak current capabilities of the drive distribution circuitry. The high currents involved generate more heat and noise than would be the case if lower currents could be employed.
One way to reduce to spread the load over a longer firing period is to fire each nozzle sequentially. Where only a relatively small number of nozzles are involved, the delay involved in firing each nozzle individually may be acceptable. However, where large numbers of nozzle are involved, such as in a pagewidth printer, the delay for firing all nozzles will frequently be unacceptable, as may be the skew of the dots on the page caused by the relatively long firing sequence.
It would be desirable to provide a method of expelling ink from a printhead module, in such a way that peak current requirements are reduced compared to simultaneous firing of all nozzles. It would also be desirable if, at least in a preferred embodiment of the invention, the printer controller was able to output control signals that directly or indirectly selects how firing of the nozzles will take place.